ABSTRACT
Adolescence is a key period for the formation of the self. Erikson (1968) named adolescence as the critical period of identity formation, which inspired Marcia (1966) to design the identity status model, which in turn led to the longitudinal study of adolescent identity formation from the 1970s on. The systematic study of personality in adolescence originates from the 1990s, after the introduction of the Big Five taxonomy of personality by McCrae and Costa in 1987. Longitudinal research into adolescent personality development emerged in the first decade of the twentieth century. Identity and personality development are the core topics of this chapter, while additional findings on development of self-concept clarity and mood will also be discussed. The chapter focuses on the description of the development of identity and personality. It presents empirical findings on mean-level change, rank-order stability, profile stability and developmental trajectory chains. Owing to the limitations of space, I use findings of meta-analyses or systematic reviews when available. Across models, the chapter shows systematic maturation of identity and personality in adolescence.
